CO2/CH4 adsorption separation process using pore expanded mesoporous silicas functionalizated by APTES grafting

Abstract

In this work we have studied the CO2 adsorption capacity and CO2/CH4 separation on several APTES-grafted mesoporous silicas of SBA-15 type. The synthesis was modified in order to obtain pore expanded materials, and post synthesis functionalization was carried out by grafting with APTES (by immersion in 20 % v/v solution). The samples were characterized by elemental (CNH) analysis, X-ray diffraction, N2 adsorption–desorption isotherms at −196 °C, and TGA. To test the CO2 adsorption capacity and CO2/CH4 separation of all samples, a gravimetric method with a magnetic suspension balance (Rubotherm, Germany) was used. Monocomponent and mixture adsorption isotherms were measured at 25 °C. All isotherms were recorded to 10 bar. Monocomponent experimental data were fitted to Langmuir and Dual-site Langmuir models and the mixture experimental data were well fitted to Multiregion Extended Langmuir combined with Dualsite Langmuir model, achieving a good correlation between experimental and simulated data.